The day our universe dies: A scientific storytelling

Dr Irengbam Mohendra Singh
Like all men beneath their skin, I’m worthless.It’s a male thing of putting blame elsewhere. I still can’t understand the geometry of Einstein’s four-dimensional universe that is flat and bendy. I can only think of living in a three dimensional universe. The fact that the sky is mainly dark at night is proof that the universe is expanding with all the countless stars moving away in all directions. It is part of the evidence that the universe must have had a beginning at some finite point, long time ago. Scientists are now talking about the likely cremation of our universe in about 22 billion years when the last stars have decayed to almost nothing.The universe then will plunge into darkness forever. They call this demise the “Big Crunch” or “Big Freeze”. I’m not worried. It’s too far away in my imagination. At my age, I’m aware there’s lessand less time left as the days go by. Every day I ache a bit more. But I’m concerned only with how I’m going to merge with the atoms of the universe.
Having traced the birth of our cosmos with the Big Bang 13.8billion years ago, and observed its growth to adulthood, they are now considering how it’s going to end.Quantum mechanics has an alternative version of the Big Bang theory. In simple terms, the theory states that the universe will continuously repeat the cycle of the Big Bang, followed up with a “Big Crunch”. This is similar to Hindu life cycles of birth and death ending up with moksha(liberation in Sanskrit).
Many scientists have compared the human lifetime with the lifespan of the Universe. And I find it fascinating, considering the modern concept of old age as the’third stage’ of human lifespan.
Until about 25 years ago in late 1980s, according to biologists, human life had two main stages: childhood and adulthood. During the childhood phase, the probability of death is extremely low, while in adulthood, the probability of death is low. Following late adulthood, as time passes, our bodies begin to decay. As a result, the probability of death increases, first slowly and then faster and faster as we become older and older.
Only in early 1990s, scientists realised that human lifespan has another part, a ‘third part’ known as the “late life”, which is characterised by a unique structure of mortality. The annual growth mortality is a feature of adult life, and does not apply to late life. For,the chance of imminent death is higher in a 60-year old than in a 50-year old. But for a 90-year old, the chance to die is about the same as a 100-year old. (cf. Lawrence Mueller, University of California, Irvine).
While I was practising medicine, I would not treat patients over 80 with (systolic) hypertension with medications (unless as an emergency with a nosebleed) as research on the effect of treatment of high blood pressure to reduce risk of heart attack and stroke were done only up to the age of 80. The understanding was that treatment would make no difference in its outcome. Rather, it was considered that, the increased blood pressure is required to maintain blood flow to the brain with advancing age, or could reflect a survivor effect. It was because arteries in the brain have no intrinsic nerve supply to adjust their blood pressure.
What’s not studied as yet, is the mortality in adulthood for a new breed of people, born in 1981-1996 (22-37 year olds), known as ‘millennials’. In these 25 years,according to the Diagnostic and Statistical Manuel of Mental Disorders, the status of adulthood has changed remarkably. These millennials, having just reached adulthoodwith a sense of privilege and entitlement, are behaving like ‘deluded narcissists”, and demanding attention. The number of these with “narcissistic personality disorder”(normally men) has gone up in an epidemic form from the pre-millennial of 6.2% (people who were born before 1981) to around one fifth of the British populationin 2015, with things like cosmetic dentistry to enhance their ego on selfies with smart phones.
The figureof this vintageinfantilising obsession is far behind Meiteis(men) of Manipur, me, me, me… eina mahelle(I’m exceptional in Manipuri). It has now caught up with odd young Meitei women, not realising what Horace Walpole once said: “The world is a comedy to those that think; a tragedy to those that feel.”Americans are just catching up with Meiteis. The Higher Education Research Institute in California, concludes that the number of adults who describe themselves as “Exceptional” compared to their peers is increasing.
Cosmologists are unanimous about the birth of our universe with the Big bang. It’s based on (1) Hubble’s observation in 1929 of the expanding universe; (2) discovery ofCosmic Microwave background (CMB) radiation in 1964 by Penzias and Wilson; and (3) mapping of CMB radiation by NASA’s COBE Satellite in 1989.The theory itself is being constantly revised and updated by studying the rate of expansion, average density of matter and the physical properties of mass and energy in the Universe. In 2001, a highly specialised microscope (WMAP) was launched from the Kennedy Space centre, in Florida that captured the faint glow of the CMB, the earliest possible photograph of the Universe.
Cosmologists believethatour Universe (there may be other universes) will die one day. Their hypothesis isbased on physical findings, such as the present state of the Universe, the dynamics of the universein the past 14 billion years, and the observation of the explosivedemise of stars like GRB090423. They have formed a probable account of how it will end.
The way the Universe is expanding, it won’t be tearing itself apart for at least a few billion years.When it does, it will bebecause of the continuing expansion of the Universe at an increasing rate and everything in it drifting apart. The stars will die out having spent their energies, and ultimately the Universe will cool down into an eternal demise called “heat death”.
The accelerated expansion of the Universe is thought to be due to ‘dark energy’ (antigravity), consisting of neutrinos and the like. It makes 68% of the Universe, while ‘dark matter’ (gravity) adds up to 27%. ‘Normal matter’ is only about 5%. As the total amount of dark energy is increasing, the expansion of the Universe acceleration will eventually reach a point where the ‘fabric’ of space-time tears itself apart and the Universe goes caput.
The era of the Universe after its birth, in the first 100 million years, is called the “Primordial Era” in cosmology. In this epoch, dust, gas and dark matter formed the galaxies due to gravity. That was followed by the “Stelliferous era” of star formation and the beginning of the “Age of light”. This was the beginning of our observable Universe today, which is 13.8 billion years old.
Our Sun, one of the billions of stars in the Universe, was formed 4.57 billion years ago from a collapsing cloud of hydrogen and helium and a sprinkling of heavier elements. It was only in the 20th century that scientists discovered that the Sun’s fires must dim one day when it runs out its nuclear fuel as hydrogen is continuously combined to helium by nuclear fusion.
Stars like the sun,get their energy from nuclear reactions (nucleosynthesis) in their cores, forming new elements. Like the Sun, when all the stars run out of their nuclear fuel, they will die in a dramatic fashion. They will collapse in an instant and release massive energy like heat. Scientists know this because they have observed the explosive death of the star, GRB 090423 in 1867.
Some cosmologists have painted a frightening scenario of the death of our Universe like the Hindu Mahapralaya, thoughit’s really in the realm of speculation. It’s a bit like a science fiction. Our sun is now in the middle of its life by fusing hydrogen into helium at a rate of about 600 million tones every second. When exhausted in another 5 billion years, it will die with its core collapsing in itself forming a white dwarf like any other star. Before that, its last release of energy will cause its outer layers to expand. Its diameter will increase by around 250 times and its extra heat will reach Earth.
Our planet earth will get hotter and hotter, our oceans will boil away and ultimately the Earth along with everything on it will melt away into nothingness. Likewise, such death must come to all stars, plunging the cosmos one day into complete darkness. In this way, countless billions of stars eventually will die in their old age. Only then the white dwarfs and black holes will remain in the Universe for billions and billions of years.
A new phase known as “The Degeneration Era” will begin, when the stars will decay. Once the last remnants of thestars have decayed, known as the “heat death” our Universe will remain cold, desolate and unchanging for the rest of time, and time will cease to exist.
Though they haven’t said what will happen to humans living on Earth, you can pretty much guess.But why to worry? We might as well enjoy the beautiful moonlight while we can.
The writer is based in the UK

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